The Kelsey Hayes tandem master cylinder found on a 1963 Corvette is a rare and valuable piece and should be handled in such a manner. All care should be taken to preserve the integrity and appearance of this cylinder. The rebuild kit will contain one or more parts not necessary to the rebuilding of the master cylinder for a 1963 Corvette. Follow the instructions and do not attempt to install these parts, as a total brake failure will occur. Replace all the used parts with the exact replacement only and discard the rest.
Tools Used: 3/8-inch drive ratchet, Set of 3/8-inch drive sockets, Brake-cylinder honing tool, Drill, Brake fluid, Set of line wrenches, Siphon, Snap-ring pliers, Can of brake cleaner
Rebuild Master Cylinder
Siphon the brake fluid from the master-cylinder reservoir. Mark the two brake lines. They need to be installed in the same location. Remove the brake lines using the line wrenches. Loosen both caps for the front and rear brakes, to which the brake lines were attached, using line wrenches.
Remove the master cylinder by removing the nuts securing it to the firewall, using the appropriate socket. Remove the two caps for the front and rear brakes previously loosened. Remove a washer, perforated cap, spring and O-ring from each cylinder.
Remove the rubber boot from the rear of the master followed by the snap ring, which holds the pistons in the bore. Remove the front and rear pistons and all the hardware from the bore. Lay them out just as they are removed, to make it easier to reassemble. Remove the master cylinder cap.
Hone the master-cylinder bore using some brake fluid on the stones to keep them wet. Hone the cylinder just enough to make it smooth and remove the pits. Keep the hone moving in and out so it does not cut into the bore or make it uneven. When you are finished honing, spray the inside of the bore with brake cleaner, to remove all residue.
Lay the new rebuild kit out next to the old parts. Match up the O-rings, rubber skirts, springs and perforated cups. The smallest spring included in the kit is for a later model, so discard it.
Assemble the front piston, which is the last part that came out of the bore. Install the new skirt on the rod followed by the O-ring. Install the small boot inside the spring and place the spring-and-boot combination over the rod. Compress the spring on the rod with your fingers and place the retaining metal cup with the split over the rod and under the flattened head of the rod. It keeps the cup in place so it can't come off, and retains the spring. Pour some brake fluid over the entire piece just assembled. Insert it into the bore and push it in with a finger.
Place the new O-ring on the small piston, keeping the front of the piston with the cone end facing toward the rear of the master. Pour brake fluid on this piston and insert it into the cylinder bore, followed by the long spring and end cap.
Insert the skirt and washer into the bore, making sure to face the skirt opening toward the parts just installed. Insert the last long piston into the bore followed by the skirt facing in. There is spring pressure needed to push the skirt into the bore, so use a finger and push in on the skirt and install the snap ring with the other hand. Install the rear dust boot.
Install the new O-rings and perforated cups in the front and rear brake cylinders on the side of the master cylinder. Install the caps and tighten them securely. Install the master cylinder in reverse order of removal, but do not tighten the brake lines. They need to be loosened to bleed the brakes.
Fill the master cylinder with fluid. Loosen either brake-line fitting and have a helper push the brake pedal down and hold it down. Do not let up on the brake pedal until the brake-line fitting is tightened slightly or air will be drawn into the system, defeating the purpose of bleeding the brakes. Tighten the fitting slightly and allow the brake pedal to rise. Loosen the same fitting and again depress the pedal and hold it down until all the air is removed and solid fluid is the only thing escaping. Once completed do the other brake line the same way.
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